Short- and Long-term Clinical Outcomes of Balloon-expandable Versus Self-expanding Valves in Patients Undergoing Transcatheter Aortic Valve Replacement: A Meta-analysis

Background: Distinct clinical differences exist between balloon-expandable valves (BEVs) and self-expanding valves (SEVs) used in transcatheter aortic valve replacement (TAVR) for aortic stenosis. However, randomised data on comparative outcomes are limited. The aim of this meta-analysis was to analyse the differences in short- and longer-term clinical outcomes between the two valve designs. Methods: A comprehensive literature search for all studies up to and including April 2020 on the clinical outcomes of BEVs versus SEVs was performed. Study outcomes were divided into short term (in-hospital or 30 days), intermediate term (1 year) and long term (3 years). The primary outcome was all-cause mortality. Secondary endpoints were stroke or transient ischaemic attack (TIA), life-threatening or major bleeding, at least moderate paravalvular leak (PVL), permanent pacemaker (PPM) implantation, aortic valve area (AVA) and aortic valve mean pressure gradient (AV MPG). Results: A total of 41 studies (BEV, n=23,892; SEV, n=22,055) were included. At in-hospital/30 days, all-cause mortality favoured BEV (OR 0.85; 95% CI [0.75–0.96]). BEV had lower rates of PVL (OR 0.42; 95% CI [0.35–0.51]) and PPM (OR 0.56; 95% CI [0.44–0.72]), but smaller AVA (mean −0.09 cm2; 95% CI [−0.17, 0.00]) and higher AV MPG (mean 2.54 mmHg; 95% CI [1.84–3.23]). There were no significant differences in the incidence of stroke/TIA or bleeding between the two valve designs. At 1 year a lower PPM implantation rate (OR 0.44; 95% CI [0.37–0.52]), fewer PVLs (OR 0.26; 95% CI [0.09–0.77]), smaller AVA (mean −0.23 cm2; 95% CI [−0.35, −0.10]) and higher AV MPG (mean 6.05 mmHg; 95% CI [1.74–10.36]) were observed with BEV. No significant differences were observed in mortality, stroke/TIA or bleeding. There was no significant difference in mortality at 3 years between the two valve designs. Conclusion: In the short–intermediate term, SEVs had better valve haemodynamics but had higher PVL and PPM implantation rates than BEVs. However, there were no differences in intermediate–long-term mortality, stroke or TIA, or bleeding complications. A better understanding of these differences will enable TAVR operators to tailor their valve choice based on individual patient profile.